Qantas has being having maintenance incidents for a few years and that is with the current maintenance workforce.
They seem to be having more problems than the Asian based carriers. This may be due to things out of their control, but it does reflect badly on their maintenance personel and or proceedures.
Which in turn dilutes the arguement that safety standards will drop if the work is carried out overseas.
As someone with a background in maintenance and the management of a maintenance workforce (albeit not in the aviation industry), I'd be looking at these likely explanations:
1. The asset itself is being run down through either incresing age and/or reduction in preventative maintenance.
2. Generic faults in particular aircraft type of a certain age. Such issues are common in other fields, and result in huge spikes in failure rates once the critical running hours are reached. This seems somewhat unlikely with Qantas however, given that other airlines operate identical aircraft such that any generic problems ought to be known to the manufacturer by now.
3. The workforce may be distracted and thus prone to making mistakes and/or not carrying out proper fault finding (which with any complex system is a damn hard thing to do at the best of times).
There are other possibilities, but I suspect that all of these apply to Qantas and have done so for quite some time.
As for outsourcing maintenance, it is always a huge liability to not have critical responses in house. Outsourcing works fine under business as usual circumstances but fails spectacularly in a crisis unless you really are the contractor's number one client and thus priority (which I'd expect Qantas isn't). The loss of technical skills in any situation such as this will in and of itself increase costs, no matter what wages anyone is being paid or what country they are from.
I've never, ever seen an outsourcing situation where the contractor didn't cut at least try to cut corners somewhere. It's not the work that they do which is the problem, you can check that, it's the things they don't do because there's nothing in writing requiring it that are the problem. You'd need a barrow load of proceedure manuals to cover everything, and odds are there's still a loophole somewhere.
My own preference for not flying Qantas has nothing to do with Joyce, unions, service standards or the comfort of seats. It all comes down to one thing - safety. It seems to be a regular occurrence that a Qantas flight makes an unplanned landing due to mechanical problems and I know all too well that there's a relationship between the number of near misses and the probability of a major incident. This airline has far too many near misses for my liking and sadly, it won't surprise me in the slightest when I turn on the news someday and hear that a Qantas plane went down.
That factor, the apparent lack of safety, is the reason I don't like flying Qantas these days. I really don't care about seats, food or the politeness of staff but I sure do care about getting from A to B alive. I prefer airlines that aren't in the news too often for this reason.